The purpose of this Ruth L. Kirschstein National Research Service Award (NRSA) Individual Pre-Doctoral Fellowship in Nursing Research (F31) application is to provide research training for Megan Streur, a third year doctoral student at the University of Pennsylvania School of Nursing. The long term goal of this training is for the applicant to develop into an independent nurse researcher with an interdisciplinary program of research focused on atrial fibrillation (AF) symptoms and self-management. AF is the most common sustained cardiac arrhythmia and the prevalence is projected to rapidly rise due to the aging of the population. Most individuals with AF experience symptoms, with the symptoms often resulting in significantly reduced quality of life. Increased knowledge of the factors influencing AF symptom perception will ultimately lead to the development of individualized interventions that improve AF symptoms and self-management. In addition to directly supporting the research described below, this NRSA training grant will support the applicant's training through the provision of directed studies, coursework, and mentorship related to topics such as symptom clusters, multivariate data analysis, responses to chronic illness, mixed-methods research, and the responsible conduct of research. The research project proposed in this application will examine AF symptom perception, defined as the physical detection of symptoms combined with the interpretation of symptom meaning. Specifically, this study aims to: 1) examine symptoms detected by adults with AF and identify symptom clusters; 2) explore how adults with AF interpret the meaning of AF symptoms; and 3) describe differences in symptom interpretation based on detected symptom clusters using integrated quantitative and qualitative data. The applicant proposes an embedded QUAN + qual concurrent triangulation mixed-methods study. The study sample will consist of 108 adults selected using purposive maximum variation sampling, with a subset of at least 20 participants participating in the qualitative interviews. Data collected will include questionnaires, medical record review of clinical data, and qualitative interviews regarding the interpretation of symptom meaning. The symptom questionnaire data will be examined for the presence of symptom clusters using agglomerative hierarchical cluster analysis. Qualitative interviews will be coded and analyzed to explore the interpretation of symptom meaning. Finally, symptom cluster data and codes from the qualitative interviews will be triangulated to describe differences in symptom interpretation related to symptom cluster membership. Both the short and long-term goals of this NRSA application align with the strategic mission of The National Institute of Nursing Research because of the focus on AF symptoms, symptom clusters, and self-management.